JPH0338915Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a speed change switch, such as a speed change switch, which controls opening/closing of a power source and output voltage.

A conventional speed change switch will be explained with reference to FIGS. 1 and 2. The solid line in FIG. 1 shows when the trigger 3 returns to the off state. The dotted line indicates the movement of the trigger 3 and the movable piece 6 when the trigger 3 is pulled by an amount a. When the trigger 3 is pulled by an amount a, the push rod 7 also moves to the right by an amount a, crosses the support plate 5, and is pushed by the spring 8a, so the movable piece 6 contacts the terminal 4b as shown by the dotted line, terminal 4a → support plate 5, movable piece 6, It is turned on through the power supply. terminal 4
b, 4c are connected to the board assembly 12. Further, a variable resistor provided on the board assembly 12 changes in conjunction with the amount of movement of the trigger 3, so that the output voltage of the terminal 4c changes depending on the amount of movement of the trigger 3.

Here, terminal 4a is a power supply terminal, 4b is an input terminal to the board assembly, and 4c is an output terminal of the board assembly.
The output voltage is controlled only while the movable piece 6 is on the terminal 4b. The speed at which the movable piece 6 comes into contact with or leaves the terminals 4b, 4c needs to be opened and closed quickly to reduce arcing.
A step δ is provided between the terminals 4b and 4c.

When the movable piece 6 contacts or separates from the terminals 4b and 4c, a voltage of 30% of the power supply voltage is applied between the terminals 4b and 4c.
Since there is a voltage difference equivalent to ~40%, arcing occurs when opening and closing. Therefore, the movable piece 6 and the terminals 4b, 4
It is effective to open and close c at a fast speed to reduce arcing.

If the trigger 3 is pulled quickly, the movable piece will vibrate due to the step δ between the terminals 4b and 4c, and when sliding on the inclined surface 9 of the movable piece, the contact between the movable piece 6 and the support plate 5 will be reduced by the push rod 7. Pressure alone cannot follow this and the contact part separates and generates an arc, which often roughens and wears out the fulcrum 5a on the upper part of the support plate 5 and the inclined surface 9 of the movable piece 6, shortening the life of the switch and preventing the switch from moving. This often resulted in poor movement of one end and unstable output voltage.

The purpose of this invention is to eliminate the drawbacks of the conventional technology, stabilize the electrical contact between the support plate and the movable piece, eliminate roughness and wear of the sliding surface of the movable piece and the support plate due to arc generation, and improve the lifespan. be.

A brush with spring properties that can follow even if the contact part between the support plate and the movable piece rises slightly is added, and the contact part is made at two places.

The basic energization path is the same as before, with the effect of damping the vibration of the movable piece by bringing it into contact with the movable piece using a weak spring pressure using a beryllium copper plate, and in the event that the movable piece floats above the support plate, it can be brought into contact with a brush. Therefore, arcing can be prevented.

The present invention will be explained with reference to FIGS. 3 to 7. 1 is a cover, 2 is a box, 3 is a trigger, and 12 is a board assembly on which electronic parts are mounted. Terminals 4a, 4b, 4c and a support plate 5 are fixed to the box 2.
The trigger 3 is assembled with a spring 8a, a push rod 7, a slider for interlocking with the variable resistance of the board assembly, and the like. The movable piece 6 is a push rod 7 attached to the trigger.
and the support plate 5. The overall shape is
As shown in FIG. 6, grooves 6a are provided in the inclined portion 9 in which the arm portions 10a of the brush 10 are accommodated, and support plates 5 are provided on both sides.
Create a sliding surface 6c. A groove 5b in which the arm part 10a of the brush 10 is accommodated is provided in the center of the tip of the support plate 5, and fulcrums 5a of the movable piece are formed on both sides. brush 10
is made of a thin plate such as beryllium copper which has spring properties and good conductivity, and has a pressure contact part 6a for joining the arm part 10a which applies preload to the groove 5b of the support plate 5 and the movable piece 6. The brush 10 and the movable piece 6 stabilize the joint by welding, welding, caulking, or the like.

Figure 4 shows a diagram when assembled. Due to the springiness of the brush 10, it is always in contact with the support plate 5, and the contact with the support plate 5 is made by two parts, the movable piece 6 and the brush 10.

According to the present invention, a spring brush is inserted between the support plate and the movable piece to prevent the vibration of the movable piece, so that the support plate and the movable piece are not separated from each other, and arc generation can be prevented. It is possible to provide a speed change switch with a long life of the energized part and stable control characteristics. Further, in the present invention, since the elastic brush moves integrally with the movable piece, the contact sliding area of the elastic brush with respect to the support plate is increased, and the life of the elastic brush is extended.

[Brief explanation of the drawing]

FIGS. 1 and 2 are cross-sectional views showing a movable piece of a conventional speed change switch, respectively. FIG. 3 is a sectional view showing the speed change switch of the present invention, and FIG.
FIG. 5 is a perspective view of the brush of the present invention, FIG. 6 is a perspective view of the movable piece of the present invention, and FIG. 7 is an enlarged view of the movable piece of the present invention. It is a perspective view of a support plate. 2 is box, 3 is trigger, 4a, 4b, 4c
is a terminal, 5 is a support plate, 5b is a groove, 6 is a movable piece, 6
6b is a groove, 6c is a sliding surface, 7 is a push rod, 10 is a brush, 10a is an arm of the brush, a is a trigger stroke, and δ is a step between terminals.

Claims (1)

[Scope of utility model registration request] A trigger 3, a fixed contact 4a, a movable piece 6 that is moved in the direction in which the trigger 3 is pulled in when the trigger 3 is pulled, and a supporting point 5a at the upper end of the movable piece 6 that supports the bottom surface of the movable piece 6 and that is fixed. A pressing force is applied to the support plate 5 connected to the contact point 4a and the upper surface of the movable piece 6, so that the lower surface of the movable piece 6 is pressed against the support plate 5.
When the trigger 3 is pulled in an initial predetermined distance, the movable piece 6 rotates about the fulcrum 5a of the support plate 5, and One end of the movable piece 6 comes into contact with the fixed contact 4b to maintain the initial switch-on state, and the other after the switch-off, where the movable piece 6 and the fixed contact 4b come out of contact due to further movement of the trigger 3 after the first switch-on. It includes the fixed contact 4a with which one end of the movable piece 6 contacts and maintains the switch-on state again, and the fixed contact 4c with a step, and changes the output voltage according to the amount of movement of the trigger 3 in the initial switch-on state. In the speed change switch, a groove 5b is formed in the upper part of the support plate 5, and one end thereof is connected and fixed to the lower surface of the movable piece 6 between the movable piece 6 and the support plate 5, and the free end side A speed change switch characterized in that a conductive elastic brush 10 is disposed in contact with the bottom of the groove 5b with pressure.